Dyn-E-Max variable exhaust nozzle - RC Groups
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Oct 25, 2008, 12:45 PM
BladeRunner
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Dyn-E-Max variable exhaust nozzle


Hi all,
Does anyone know where I can get a variable exhaust nozzle. A few years ago I thought there was one available. Any information would be helpful, would like to have one for my Dyn-E-Max fan unit.

Fred.
Last edited by bladexz2; Oct 25, 2008 at 10:50 PM.
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Jan 31, 2009, 03:27 PM
Registered User
Hi Fred -

Presently, I am working on a variable (adjustable from transmitter) flow nozzle.

It is suitable for both inlet and outlet ducting, it is sized for the midi-fan.

When the R&D is finished, I will scale it up for the larger fans, provided of coarse, that it proves to be effective.

First operational trials set for next week.

Ron
Jan 31, 2009, 04:27 PM
Suspended Account
Good luck with that Ron!

Keen to see what you have engineered when you are done.

Steve
Jan 31, 2009, 06:49 PM
John Green
The first is a unit which once was commercially available. I have it in a IC F-16 and it is as yet untested. The other two are solutions I have found here in the threads and seem to use the same principle.

John
Last edited by PlumberJohn; Jul 20, 2010 at 08:01 PM.
Jan 31, 2009, 07:19 PM
Need 4 Speed!
pdawg's Avatar
The fastest glow powered ducted fan I've ever seen (possibly the fastest ever) was a BVM viper with a variable exhaust nozzle. The builder was from the Los Angeles area and this was in the late 90's. he was the designer of the varible nozzle and it was controlled by an onboard airspeed sensor (pretty hi-tech for the time). I believe it was officially clocked in the mid 220's on several occassions. I can personally say this was no joke. It came out of a huge split-S (like all the other DFs) and it was clearly a notch above everything else. I doubt any other glow powered DF every had a chance against this guy and his highly fluorescent Viper.

P.S. I also know that Corsair Nut also saw this model in action and he was left with a very similar impression.
Latest blog entry: original Y/A F-18 Kit
Jan 31, 2009, 09:43 PM
Registered User
The guys name was Paul Ivie , I think that spelling is correct. I don't think he manufactures them anymore. I have 3 variable exhaust nozzles, the one in the picture , and 2 home made . One is made from aluminum and the other out of cardboard for a small electric F16. I have flown the 2 large ones and they worked good , however the mixture would lean out when necked down due to an increase in the air velocity which caused a decrease in pressure in the duct. A servo controlled remote needle valve had to be used . I found about a 15-20 mph increase in level top speed but the aircraft they were used on were not very fast to begin with so any increase was good. I can post some pictures on Monday night .

Todd
Feb 01, 2009, 02:26 AM
Need 4 Speed!
pdawg's Avatar
Todd,

Yep it was Paul Ivie. Looking forward to your pics as well as Ron's test results.
Latest blog entry: original Y/A F-18 Kit
Feb 02, 2009, 08:01 PM
Registered User
Here are the pics of the three variable exhaust nozzles i have. The black one is built from a kit by Paul Ivie. The aluminum one i designed and built myself from aluminum. ( no it is not a Bob Fiorenza nozzle). And the brown one is my own design built from a paper cup for a Phase 3 F16.
The aluminum nozzle works fine but i felt i was getting metal to metal interference so i quit using it.
Todd
Feb 02, 2009, 10:12 PM
Need 4 Speed!
pdawg's Avatar
Todd,
Those are all pretty cool and are sure to be revived in the future. As I remember the Paul Ivie one had a ring that narrowed the outlet when it was pulled forward. THe metal one looks awesome. Maybe it wouldn't cause interference with the 2.4 systems? Nice work!
Latest blog entry: original Y/A F-18 Kit
Feb 03, 2009, 11:07 AM
dare to be dull
bigjohn's Avatar
Bob Fiorenze used to market a metal one. It's not on his page but might be worth a call.

http://www.rcaviation.com/fiorenze/
Feb 04, 2009, 02:39 PM
Registered User
Quote:
Originally Posted by pdawg
Todd,
Those are all pretty cool and are sure to be revived in the future. As I remember the Paul Ivie one had a ring that narrowed the outlet when it was pulled forward. THe metal one looks awesome. Maybe it wouldn't cause interference with the 2.4 systems? Nice work!
Actually the Paul Ivie nozzle uses 2 small plastic coated cables that run through a bunch of 1/8 in. square carbon fiber rods and when the cables are pulled the nozzle contracts and when released the air pressure opens it back up. A retract servo was required for this job it took a lot of power to close the nozzle down at full power.
This was a well made kit that took a couple evenings to build . I hope to have it up and flying again this summer on a E-turbax ,but it will be a Turbax 2 (4 in. fan) with a Scorpion outrunner . Turns about 25,000 rpm and gives me 6.5 lbs thrust at only 45 amps on 10s lipol. That was about 1500w.
Todd


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